Lorentz-Force Actuated Cleaning Device

ABSTRACT

A method of surface treatment includes sensing a surface condition and controlling ejection of a fluid jet against the surface to treat the surface based on the sensed condition. The fluid may be a liquid and may be carried in a self-contained reservoir in a handle of a fluid ejection device. The liquid can be a cleansing solution and may contain cleaning particles. The ejection can be controlled to clean a part of the surface at high pressure and to reduce pressure applied to another part of the surface, for example, to clean the surface. The method may further include automatically scanning the fluid jet relative to a handle of an injection device. In an embodiment, the fluid is ejected by means of a fluid ejector comprising a stationary magnet assembly providing a magnetic field and a coil assembly, slidably disposed with respect to the magnet assembly, the coil assembly driving ejection of the fluid jet. Sensing the surface condition can include measuring a response of the surface to a mechanical perturbation and may include sensing an acoustic signal reflected from the surface. The mechanical perturbation can include applied force and the measured response can include deformation of the surface. The method may further include mechanically disturbing the surface with the fluid jet. A surface treatment device includes a fluid ejector that ejects fluid against a surface and a servo controller controlling pressure of ejected fluid in response to a sensed surface condition. The fluid jet can have a diameter of less than 500 microns, a peak relative pressure of at least 1 kilopascal and velocity of at least 1 meter per second.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/286,632, filed on Dec. 15, 2009, and U.S. Provisional Application No.61/286,651, filed on Dec. 15, 2009. The entire teachings of the aboveapplications are incorporated herein by reference.

BACKGROUND OF THE INVENTION

In the oral cavity, indigenous bacteria are often associated with twomajor oral diseases; caries and periodontitis [H. Marcotte and M. C.Lavoie, Oral microbial ecology and the role of salivary immunoglobulinA, Micro Mol Bio 62 (1998) 71-109]. The diverse structures within themouth (i.e. the tooth surface, subgingival space, and tongue) supportseveral different microbial communities. The supragingival environmentof the oral cavity is regulated by saliva, a complex mixture of water,electrolytes (e.g. sodium, potassium, calcium, chloride, magnesium,bicarbonate, phosphate), enzymes (e.g. lysozyme, lactoferrin,peroxidase), proteins (e.g. sIgA, glycoproteins etc.), vitamins,hormones, urea and nitrogenous products. The less accessible subgingivalenvironment is bathed by the gingival crevicular fluid (GCF), a plasmaexudate containing proteins, albumin, leukocytes, immunoglobulins, andcomplement.

Good oral hygiene requires that one sustain a healthy oral ecosystem.However, the boundaries between the soft mucosa and hard teeth are ripefor bacterial colonization (e.g. the gingival crevice or sulcus). Thesulcus together with the area between the teeth (i.e. approximatesurface), and the pits and fissures of the biting surface are not easilycleaned by brushing (i.e. mechanical friction). Microorganisms tend tocolonize these areas to form dental plaque; a biofilm of microorganismsand salivary components. If not removed, plaque can lead to caries orperiodontal disease (e.g. gingivitis and possibly periodontitis). Plaqueand calculus can be removed with or without electrically driven handinstruments in the dental office. Calculus, a form of hardened plaque,forms along the gum line and within the sulcus leading to inflammationthat can eventually lead to deep pockets between the teeth and gum andloss of bone that holds the tooth in place. Human periodontitis isassociated with a widely diverse and complex subgingival microbiota[Daniluk, T., Tokajuk, G., Cylwik-Rokicka, D., Rozkiewics, D., Zaremba,M. L., and Stokowska, W., Aerobic and anaerobic bacteria in subgingivaland supragingival plaques of adult patients with periodontal disease,Adv Med Sci 51: (2006) 81-85].

While there are commercially available water jet devices for dentalcleaning, they are limited for the most part to the removal of debris.The pumps used in these units are often noisy, which can contribute topatient discomfort. Seating or mating the tip with the water jet issometimes problematic leading to leakage and ineffective or less thanoptimal irrigation. While some devices have adjustable controls, many donot provide good control.

Sensing devices for diagnosing oral health and/or hygiene are currentlyeither in the research and development stage or are formatted for use bytrained professionals. Many devices are not user friendly and notsuitable for day to day use by consumers.

Issues faced in dental cleaning, e.g. the removal of bacterial film orplaque, are relevant to other medical, non- medical, and industrialcleaning and surface treatment applications, including, for example,cleaning of household appliances, such as ovens, and treatment andcleaning of surfaces, such as surfaces in bathrooms and kitchens. Anappliance typically includes surfaces having different properties orsurface conditions, and may be treated or cleaned differently. Ingeneral, cleaning of medical and household appliance may involveremoving grime, grease, lime scale, bacterial film and/or mildew fromthe surface of the appliance.

SUMMARY OF THE INVENTION

A method of surface treatment includes sensing a surface condition andcontrolling ejection of a fluid jet against a surface to treat thesurface based on the sensed condition.

The fluid may be a liquid and may be carried in a self-containedreservoir in a handle of a fluid ejection device. The reservoir can beless than 100 milliliters. The liquid can be a cleansing solution andmay contain cleaning particles.

In one embodiment, the fluid jet is of a diameter of less than 500microns. The jet may be of a diameter of less than 200 microns. Theejection may be controlled at a bandwidth of at least 10 Hertz, of atleast 50 Hertz, of at least 100 Hertz, or of at least 1 kilo Hertz. Thefluid may be ejected at a peak relative pressure of at least 1kilopascal or of at least 100 kilopascals, and at a velocity of at least1 meter per second or of at least 10 meters per second. The ejection canbe controlled to clean a part of the surface at high pressure and toreduce pressure applied to another part of the surface. The fluidejection may be controlled to clean the surface. Less than 100milliliters of liquid may be ejected per cleaning session. In someembodiments, the method may further include automatically scanning thefluid jet relative to a handle of an injection device.

In an embodiment, the fluid is ejected by means of a fluid ejectorcomprising a stationary magnet assembly providing a magnetic field and acoil assembly, slidably disposed with respect to the magnet assembly,the coil assembly driving ejection of the fluid jet.

In some embodiments, sensing the surface condition includes measuring aresponse of the surface to a mechanical perturbation. The mechanicalperturbation can include applied force and the measured response caninclude deformation of the surface. The method may further includemechanically disturbing the surface with the fluid jet. Measuring aresponse of the surface may include measuring pressure of the fluid.Measuring pressure can include sensing strain of a fluid reservoir andmay include sensing position of an actuator driving the ejection of thefluid. In an embodiment, sensing the surface condition includes sensingan acoustic signal reflected from the surface. The acoustic signal maytravel through the fluid jet and may be sensed using a piezo-electrictransducer. The method may further include generating the acousticsignal. The acoustic signal may be generated and sensed using apiezo-electric transducer, and may include a stochastic signal. Further,sensing the surface condition may include measuring surface deformationwith applied force using the sensed acoustic signal. The force can beapplied using the fluid jet. In some embodiments, the method may furtherinclude sensing motion of a fluid ejector and controlling the ejectionof the fluid jet based on the sensed motion.

A method of surface treatment includes ejecting a fluid jet against thesurface, the jet having a diameter of less than 500 microns, a peakrelative pressure of at least 1 kilopascal and velocity of at least 1meter per second. The method may be used for removing any combination ofgrime, grease, lime scale, bacterial film and mildew from the surface.Further, the method may include automatically scanning the fluid jetrelative to a handle of an injection device.

A hand-held surface treatment device includes a housing configured to beheld on hand and a fluid ejector positioned at an end of the housingthat ejects fluid against a surface in a scanning movement relative tothe housing. The scan may be greater than 1 millimeter. The device mayfurther include a servo controller controlling pressure of ejected fluidin response to a sensed surface condition, such as a mechanical propertyof the surface. Further, the device can include a pressure sensor thatsenses pressure of the fluid in the ejector. The pressure sensor mayinclude a strain gauge that senses strain of a reservoir of the ejector.Alternatively or in addition, the pressure sensor can include a positionsensor that senses position of an actuator driving the ejection of thefluid. The device may further include a distance sensor that sensesdistance of the ejector from a surface. In some embodiments, thedistance sensor includes a piezo-electric transducer and the distance issensed using an acoustic signal. Further, the device may include a servocontroller controlling pressure of ejected fluid in response to a sensedmotion of the ejector.

A method of surface treatment includes ejecting a fluid jet against asurface and scanning the fluid jet relative to a handle of an injectiondevice. Further, the method of surface treatment can include controllingpressure of ejected fluid based on a sensed surface condition and,alternatively or in addition, based on a sensed motion of the injectiondevice.

A surface treatment device includes a fluid ejector that ejects fluidagainst a surface and a servo controller controlling pressure of ejectedfluid in response to a sensed surface condition. The fluid ejector mayeject a fluid jet against the surface, the jet having a diameter of lessthan 500 microns, a peak relative pressure of at least 1 kilopascal andvelocity of at least 1 meter per second. The device may further includea housing configured to be held on hand, the fluid ejector beingpositioned at an end of the housing. Further, the device can include aself-contained reservoir of the liquid in the housing and the reservoirmay be less than 100 milliliters. In some embodiments, the device mayfurther include a pressure sensor that senses pressure of the fluid inthe ejector, and wherein the surface condition is sensed based on thesensed pressure. Alternatively or in addition, the device may furtherinclude an acoustic transducer that senses an acoustic signal reflectedoff the surface, and wherein the surface condition is sensed based onthe reflected acoustic signal.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particulardescription of example embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingembodiments of the present invention.

FIG. 1 is a schematic block diagram of one embodiment of a controllable,needle-free transfer device for cleaning teeth, gums, and other areas ofthe mouth;

FIG. 2A is a partial cut-away perspective diagram of an embodiment of acontrollable needle-free transfer device;

FIG. 2B are graphs depicting force-versus-time profiles of exemplaryforce components used for fluid delivery and for tissue identification,the force components being generated by the controllable electromagneticactuator of FIG. 2A;

FIG. 3 is a partial cut-away perspective diagram of the device of FIG.2A illustrating scanning of the device;

FIGS. 4A and 4B are graphs depicting pressure versus time, the measurebeing fluid pressure sensed using a strain gauge and a position sensor,respectively;

FIG. 4C is a graph of peak pressures sensed during ejection of fluidagainst materials of different surface properties;

FIG. 4D is a graph of pressure versus angle of injection against asurface;

FIGS. 5A-5D are perspective diagrams showing delivery of water and blackbeads to the gum line and sulcus;

FIG. 6 is a top perspective diagram of an exemplary detector fordetecting an analyte from a sample collected in a disposable tube;

FIGS. 7A and 7B are schematic block diagrams of a needle-free transportdevice providing sampling and analysis capability, respectively shown inthe sampling and fluid ejection configurations;

FIG. 8 is a top perspective diagram of an exemplary detector fordetecting an analyte using a polymer strip;

FIG. 9A is a schematic diagram showing binding of an analyte (antibody)to a solid support (polypyrrole film strip);

FIG. 9B is a graph of light absorbance versus antigen concentration;

FIG. 10 is a schematic diagram showing a detector for detecting a markeror analyte of oral health status.

DETAILED DESCRIPTION OF THE INVENTION

A description of example embodiments of the invention follows.

The entire teachings of U.S. patent application Ser. No. 10/277,722,filed on Oct. 21, 202, entitled “Impedance Sensor” (Attorney Docket No.:0050.2035-000, Client Reference No.: MIT-9486), now U.S. Pat. No.7,645,263, issued on Jan. 12, 2010; U.S. Pat. No. 6,939,323, issued onSep. 6, 2005, entitled “Needleless Injector” (Attorney Docket No.:0050.2036-001; Client Ref. No.: MIT-9496); U.S. Pat. No. 7,425,204,issued on Sep. 16, 2008, entitled “Needleless Injector” (Attorney DocketNo.: 0050.2036-016; Client Ref. No.: MIT-9496); U.S. patent applicationSer. No. 12/459,866, filed on Jul. 8, 2009, entitled “Bi-DirectionalMotion of a Lorentz-Force Actuated Needle-Free Injector (NFI)” (AttorneyDocket No.: 0050.2124-001; Client Ref. No.: MIT-13318); U.S. patentapplication Ser. No. 12/872,630, filed on Aug. 31, 2010, entitled“Nonlinear System Identification Techniques and Device For DiscoveringDynamic And Static Tissue Properties” (Attorney Docket No.:0050.2133-002; Client Ref. No.: MIT-13836); U.S. Pat. No. 7,530,975,issued on May 12, 2009, entitled “Measuring Properties of an AnatomicalBody” (Attorney Docket No.: 0050.2048-006; Client Ref. No.: MIT-9894);and U.S. Published Application No. US 2007/0191758, published on Aug.16, 2007, entitled “Controlled Needle-Free Transport” (Attorney DocketNo. 0050.2079-005; Client Ref. No.: MIT-11511) are incorporated hereinby reference. These Applications and Patents relate to sensors andinjectors that may be utilized in implementing the present invention.

Embodiments of the present invention relate to a needle-free device forcleaning the teeth, the gums, and other areas of the mouth. Theembodiments of the present invention may be used for cleaning anddiagnosis of dental and medical conditions in human or animals. Certainembodiments include a fine jet injector that transfers high pressuredliquid (e.g., water, liquid designed for cleaning of the mouth, liquiddesigned for diagnosis of medical or dental conditions, and etc.) toremove and blast off plaque from the human teeth. The jet injector isservo-controlled to transfer the liquid and control the pressure of thefluid in the vicinity of soft tissue (e.g., gums). As such, the highpressure liquid will remove plaque from the teeth without penetratingthe gums. The device may operate in real time by determining mechanicalproperties of the transfer site and distinguish between hard tissue andsoft tissue based on the mechanical properties.

The needle-free device includes an actuator capable of generating ahigh-speed, high-pressure pulse that is both controllable and highlypredictable. The device may be combined with a servo-controllerreceiving inputs from one or more sensors. Further, the device mayadjust or tailor the pressure profile of a transfer in real-time, duringthe course of the transfer, responsive to sensed physical properties oftissue and teeth. For example, the device may be able to distinguishsoft tissue (e.g., gums, gum lines, and tongue) from the teeth.

The jet injector may include sensors that detect respective physicalproperties of the transfer site. The physical properties can be used toservo control the jet injector and tailor the injection pressure, and,therefore, the depth of penetration of fluid into for a particularregion. For instance, when the device is used on the gums, the sensordetects the softness of the gums, and the controller uses the propertiesof the gums and consequently reduces the transfer pressure. The transferpressure can be adjusted, for example, by controlling the electricalinput signal applied to the injector and/or the current pulse rise timeand/or duration. When used on hard enamel (teeth), the controller mayincrease the transfer pressure. The transfer pressure may be adjusteddepending on location of the liquid transfer, for example, the gumsversus the tongue. The transfer pressure can also be tailored to delivera substance just underneath the gum line or deep into gums. Moreover,the transfer pressure may be varied over time.

Since oral plaque is usually stored as deep as one millimeter under thegum line, the controller of the needle-free device can distinguishbetween the teeth, gums, and the gum line by considering the physicalproperties of the teeth and the soft tissue and adjust the transferpressure on each of these body parts accordingly.

In certain embodiments, the needle-free injector generates a jetpressure and transfers high pressure liquid that can remove the plaquefrom the teeth. The peak liquid pressure may be as low as 1 Kilo Pascal.In some embodiments up to 100 Kilo Pascal of relative water pressure maybe applied.

Jets of less than 500 microns are generally employed. In certainembodiments, very fine jets may be employed. For example, jets havingdiameter of less than five micro meters may be employed. In oneembodiment, the jet injectors may have a diameter of less than 200micrometers.

The needle-free device is servo-controlled to transfer the fluid andcontrol the pressure of the fluid in the vicinity of soft tissue (e.g.,gums) and the teeth. Due to the high level of control offered by thedevice, the amount of fluid transferred into the mouth may besignificantly reduced. In some embodiments, a tooth cleaning liquidhaving appropriate cleaning agents may be jet injected into the mouth,teeth, or the gums to help with blasting of plaque and maintaining oralhealth. Additional substances may be included in the liquid injectedinto the mouth. For example, substances having bacteria and fungusfighting agents, whitening agents, or breath freshening agents may beemployed.

In some embodiments, the needle-free device may further include one ormore electrical impedance sensors that can be used to distinguishbetween soft tissue (gums and tongue) and the teeth. The impedancetesting also provides a convenient way of determining the depth ofpenetration. The impedance sensor may include an electrode positioned tomeasure the impedance of a portion of the target area between theelectrode and ground to indicate the depth of penetration into thetarget area.

In certain embodiments, two or more jet injectors may be employed withone of the jet injectors serving as a ground connection for impedancemeasurements. In some embodiments, a conductive fluid can be used forcleaning or diagnosis. In these embodiments, the body, through the lip,when it comes in contact with the injector, provides the groundconnection for the impedance measurements.

In some embodiments, the needle-free device includes a reservoir forstoring the fluid and a controllable electromagnetic actuator incommunication with the reservoir. The controllable electromagneticactuator may include a stationary magnet assembly providing a magneticfield; and a coil assembly. The coil assembly receives an electricalinput and generates in response a force corresponding to the receivedinput. The force results from interaction of an electrical currentwithin the coil assembly and the magnetic field and causes the transferof the fluid between the reservoir and the mouth. The needle-free devicecan include a sensor that senses physical properties of the transfersite and causes the servo-controller to generate the electrical inputresponsive to the sensed physical property. In order to measure thephysical properties, ranging techniques using acoustic waves or laserbeams may be applied to find deformation of teeth or gum lines. Acousticwaves may be used in combination with a fluid jet, where the pressure ofthe fluid jet applies a force to the target tissue to perturb the targettissue and the acoustic waves are used to sense the deformation ordisplacement of the tissue in response to the perturbation. The acousticsignal can propagate through the fluid jet and may include a sinusoidaland/or stochastic signal.

Example embodiments may include a Lorentz-Force actuator to providereversibility for the device. In such embodiments, a fluid can be pumpedinto the mouth to blast off and remove plaque and the removed materialmay then be removed from the mouth using the reversible actuator. TheLorentz force actuator exerts a force. The force can be used forneedle-free transfer of the substance between the reservoir and themouth. The injector can determine changes in response to the forces anddetermine individual target area properties based on the response to theforces. In certain embodiments, stochastic (random) or pseudo-randominformation can be employed to create a model (e.g., non-parametricmodel) of tissue properties.

Example embodiments may include a piezoelectric actuator to provide highfrequency pulses of the fluid jet. The device may have a minimumbandwidth of approximately 10 Hz (Hertz). In certain embodiments thedevice may have a bandwidth of 50 Hz, 100 Hz, or 100 KHz.

Certain embodiments may include sensors and related technologies foranalyzing materials removed from the mouth such as plaque, saliva, andetc. The analyzed results may be used to distinguish between healthy andunhealthy tissue in the mouth. In some embodiments, the liquidtransferred into the mouth may include biomarkers for verifying oralhealth and detecting possible health issues. In some embodiments, thesame liquid containing biomarkers may be used in cleaning and plaqueremoval.

In some embodiments, the needle-free device may be used in diagnosis oforal conditions. For example, the device may be used to determine if atooth has a cavity or is decaying. Since the mechanical properties of adecaying tooth are different from that of a healthy tooth, the devicecan diagnose a decaying tooth by determining a change in the mechanicalproperty of the tooth. Microelectromechanical Systems (MEMS) along withaccelerometers may be used to determine the location of a decayingtooth.

The device may be coupled to a Computer-Aided Diagnosis model of themouth to determine health status of every surface. The device maytransfer a fluid that is to be used on a daily basis for cleaning and asecond fluid for diagnosis that is to be used on a less frequent basis.Certain embodiments may employ Raman spectroscopy techniques todistinguish healthy and unhealthy tissue. The data obtained regardingthe health of the mouth may be fed into a database, or transferred,possibly via a wireless module, for further evaluation or analysis.

The device may transfer as much as 10 microliters of fluid, e.g.,liquid, per second. The liquid may be transferred at a peak pressure of1 kilo Pascal to loosen food. In certain embodiments, an averagepressure of up to 100 Mega Pascal may be used to loosen plaque. Thedevice may operate at a velocity as low as 1 meter per second (m/s). Insome embodiments, velocities as high as 10 m/s or higher (e.g., ⅔ of thespeed of sound) may be used.

Pulses can be used to dynamically control (e.g., servo-control) themagnitude, direction and duration of the force during the course of anactuation cycle. In certain embodiments, the device includes an actuatorcapable of generating a high-speed, high-pressure pulse that is bothcontrollable and highly predictable. The device also includes theability to pulse shape to use different waveforms for each cycle. Incertain embodiments, fine sinusoidal pulses may be employed toapproximate a square wave. For example, a sinusoidal pulse having abandwidth of 10 microseconds can be used.

The device may be coupled to multiple reservoirs. In one exampleembodiment, the device includes two reservoirs arranged such that onereservoir includes a larger amount of fluid compared to the otherreservoir. At each cycle, a square wave is used to control the directionand duration of the force. At each cycle a certain amount of fluid istransferred from the second reservoir into the mouth. At the end of thecycle, a limited amount of liquid is transferred from the firstreservoir into the second reservoir.

The device may also be used in drilling the teeth. Previously, dentistsremoved cavity by simply feeling soft, unhealthy enamel from the teeth(while removing healthy enamel in the process). The device can determinethe mechanical properties of healthy tooth vs. unhealthy tooth and use acombination of velocity and pressure coupled with an abrasive to drillthe unhealthy portion of the tooth and leave the healthy enamel behind.Drill heads as small as 50 micrometers in diameter may be used.

FIG. 1 is a schematic block diagram of a needle-free transport device orjet injector 100 that may be used in example embodiments. Device 100 cantransfer a substance to or from a surface of a biological body and maybe used to eject a fluid against tooth 150, gum 155, or other tissue inthe oral cavity. The jet injector 100 can be used to deposit a fluid,including a medicant or biomarker, into the space between tooth 150 andgum 155. Alternatively of in addition, the same device can be used tocollect a sample from a location at or near the tooth 150 or gum 155 bywithdrawing the collected sample into a reservoir 113

The device 100 typically includes a nozzle 114 to convey the substance.Namely, substance ejected from the nozzle 114 forms a jet, the force ofthe jet determining the depth of penetration. The nozzle 114 generallycontains a flat surface, such as the head 115 and an orifice 101. It isthe inner diameter of the orifice 101 that controls the diameter of thetransferred stream. Additionally, the length of an aperture or tube 103,defining the orifice 101 also controls the transfer (e.g., injection)pressure.

The nozzle 114 can be coupled to a reservoir 113 for temporarily storingthe transferred substance. Reservoir 113 may be a reservoir of a syringeor ampoule 112. Beneficially, a pressure is selectively applied to thereservoir 113 using a controllable actuator. A specially-designedelectromagnetic actuator 125 is configured to generate a high-pressurepulse having a rapid rise time (e.g., less than 1 millisecond). Theactuator 125 can be used in needle-free injection devices that rely onhigh-pressure actuators to inject a formulation beneath the skin. Theactuator is dynamically controllable, allowing for adjustments to thepressure-versus-time during actuation. At least one advantage of theelectromagnetic actuator over other needle-free devices is itsrelatively quiet operation. Actuation involves movement of a freelysuspended coil within a gap, rather than the sudden release of a springor the discharge of a gas. Actuation of the freely-moving coil in themanner described herein results in quiet operation, which is animportant feature as it contributes to reducing pain and anxiety duringadministration to the recipient and to others that may be nearby.

In more detail, the electromagnetic actuator 125 is configured toprovide a linear force applied to the plunger 126 to achieve transfer ofthe substance. Transfer of the force can be accomplished with aforce-transfer member 110, such as a rigid rod slidably coupled througha bearing 111. The rod may be secured at either end such that movementof the actuator in either direction also moves the plunger 126. Thebearing restricts radial movement of the rod 110, while allowing axialmovement.

In some embodiments, the actuator 125 is a Lorentz force actuator thatincludes a stationary component, such as a magnet assembly 105, and amoveable component, such as a coil assembly 104. A force produced withinthe coil assembly 104 can be applied to the plunger 126 either directlyor indirectly through the rod 110 to achieve transfer of the substance.

In some embodiments, device 100 may not include a separate bearing 111.Rather, an interior surface of the housing 102 provides a bearing forthe coil assembly 104 allowing axial movement while inhibiting radialmovement.

In some embodiments, the device 100 includes a user interface 120 thatprovides a status of the device. The user interface may provide a simpleindication that the device is ready for actuation. More elaborate userinterfaces 120 can be included to provide more detailed information,including a liquid crystal display (LCD), cathode ray tube (CRD),charge-coupled device (CCD), or any other suitable technology capable ofconveying detailed information between a user and the device 100. Thus,user interface 120 may also contain provisions, such as a touch screento enable an operator to provide inputs as user selections for one ormore parameters. Thus, a user may identify parameters related to dose,sample, parameters related to the biological body, such as age, weight,etc.

A power source 106 provides an electrical input to the coil assembly 104of the actuator 125. An electrical current applied to the coil assembly104 in the presence of a magnetic field provided by the magnet assembly105 will result in a generation of a mechanical force capable of movingthe coil assembly 104 and exerting work on the plunger 126 of thesyringe 112. The electromagnetic actuator is an efficient forcetransducer supporting its portability.

A controller 108 is electrically coupled between the power source 106and the actuator 125, such that the controller 108 can selectivelyapply, withdraw and otherwise adjust the electrical input signalprovided by the power source 106 to the actuator 125. The controller 108can be a simple switch that is operable by a local interface. Forexample, a button provided on the housing 102 may be manipulated by auser, selectively applying and removing an electrical input from thepower source 106 to the actuator 125. In some embodiments, thecontroller 108 includes control elements, such as electrical circuits,that are adapted to selectively apply electrical power from the powersource 106 to the actuator 125, the electrical input being shaped by theselected application. Thus, for embodiments in which the power source106 is a simple battery providing a substantially constant or directcurrent (D.C.) value, the electrical input can be shaped by thecontroller to provide a different or even time varying electrical value.In some embodiments, the controller 108 includes an on-boardmicroprocessor, or alternatively an interconnected processor or personalcomputer providing multifunction capabilities. A power amplifier (notshown) may be included in the controller 108 or, alternatively or inaddition, in power source 106.

In some embodiments, the needle-free device 100 includes a remoteinterface 118. The remote interface 118 can be used to transmitinformation, such as the status of the device 100 or of a substancecontained therein to a remote source, such as a hospital computer or adrug manufacturer's database. Alternatively or in addition, the remoteinterface 118 is in electrical communication with the controller 108 andcan be used to forward inputs received from a remote source to thecontroller 108 to affect control of the actuator 125.

The remote interface 118 can include a network interface, such as alocal area network interface (e.g., Ethernet). Thus, using a networkinterface card, the device 100 can be remotely accessed by anotherdevice or user, using a personal computer also connected to the localarea network. Alternatively or in addition, the remote interface 118 mayinclude a wide-area network interface. Thus, the device 100 can beremotely accessed by another device or user over a wide-area network,such as the World-Wide Web. In some embodiments, the remote interface118 includes a modem capable of interfacing with a remote device/userover a public-switched telephone network. In yet other embodiments, theremote interface 118 includes a wireless interface to access a remotedevice/user wirelessly. The wireless interface 118 may use a standardwireless interface, such as Wi-Fi standards for wireless local areanetworks (WLAN) based on the IEEE 802.11 specifications; new standardsbeyond the 802.11 specifications, such as 802.16 (WiMAX); and otherwireless interfaces that include a set of high-level communicationprotocols such as ZigBee, designed to use small, low power digitalradios based on the IEEE 802.15.4 standard for wireless personal areanetworks (WPANs).

In some embodiments the controller receives inputs from one or moresensors adapted to sense a respective physical property. For example,the device 100 includes a transducer, such as a position sensor 116Bused to indicate location of an object's coordinates (e.g., the coil'sposition) with respect to a selected reference. Similarly, adisplacement may be used to indicate movement from one position toanother for a specific distance. Beneficially, the sensed parameter canbe used as an indication of the plunger's position and therefore anindication of dose. In some embodiments, a proximity sensor may also beused to indicate when a part of the device, such as the coil, hasreached a critical distance. This may be accomplished by sensing theposition of the plunger 126, the force-transfer member 110, or the coilassembly 104 of the electromagnetic actuator 125. For example, anoptical sensor such as an optical encoder can be used to count turns ofthe coil to determine the coil's position. Other types of sensorssuitable for measuring position or displacement include inductivetransducers, resistive sliding-contact transducers, photodiodes, andlinear-variable-displacement-transformers (LVDT).

Other sensors, such as a force transducer 116A can be used to sense theforce applied to the plunger 126 by the actuator 125. As shown, a forcetransducer 116A can be positioned between the distal end of the coilassembly and the force transfer member 110, the transducer 116A sensingforce applied by the actuator 125 onto the force-transfer member 110. Asthis member 110 is rigid, the force is directly transferred to theplunger 126. The force tends to move the plunger 126 resulting in thegeneration of a corresponding pressure within the reservoir 113. Apositive force pushing the plunger 126 into the reservoir 113 creates apositive pressure tending to force a substance within the reservoir 113out through the nozzle 114. A negative force pulling the plunger 126proximally away from the nozzle 114 creates a negative pressure orvacuum tending to suck a substance from outside the device through thenozzle 114 into the reservoir 113. The substance may also be obtainedfrom another reservoir or ampoule, the negative pressure being used topre-fill the reservoir 113 with the substance. Alternatively or inaddition, the substance may come from the biological body representing asampling of blood, tissue, and or other interstitial fluids. In someembodiments, a pressure transducer (not shown) can also be provided todirectly sense the pressure applied to a substance within the chamber orreservoir 113. In addition, the position sensor 116B may sense theposition of the coil which may be used to indirectly measure thepressure within the reservoir 113.

An electrical sensor 116C may also be provided to sense an electricalinput provided to the actuator 125. The electrical sensor may sense oneor more of coil voltage and coil current. Other sensors may include forexample a gyrometer 116D, an accelerometer 116E, a strain gauge 116F, atemperature sensor 116G, an acoustic sensor or transducer 116H, and/orbarometric pressure sensor 116J. The gyrometer 116D may include a 3-axisgyroscope and the accelerometer 116E may include a 3-axis accelerometer.The sensors 116A, 116B, 116C, 116D, 116E, 116F, 116G, 116H, and 116J(generally 116) are coupled to the controller 108 providing thecontroller 108 with the sensed properties. The controller 108 may useone or more of the sensed properties to control application of anelectrical input from the power source 106 to the actuator 125, therebycontrolling pressure generated within the syringe 112 to produce adesired transfer performance. For example, a position sensor can be usedto servo-control the actuator 125 to pre-position the coil assembly 104at a desired location and to stabilize the coil 104 once positioned, andconclude an actuation cycle. Thus, movement of the coil assembly 104from a first position to a second position corresponds to transfer of acorresponding volume of substance. The controller can include aprocessor programmed to calculate the volume based on position given thephysical size of the reservoir.

An actuation cycle, generally corresponds to initiation of an electricalinput to the actuator 125 to induce transfer of a substance andconclusion of the electrical input to halt transfer of the substance. Aservo-control capability combined with the dynamically controllableelectromagnetic actuator 125 enables adjustment of the pressure duringthe course of an actuation cycle. One or more of the sensors 116 can beused to further control the actuation cycle during the course of thetransfer, or cycle. Alternatively or in addition, one or more of localand remote interfaces can also be used to further affect control of theactuation cycle.

In some implementations, the controller 108 is coupled with one or moresensors 116, or one or more other sensors (not shown), that detectrespective physical properties of the biological body. This informationcan be used to servo control the actuator 125 to tailor the injectionpressure. For instance, when the device 100 is used on the gums, thesensor detects the softness of the gums, and the controller 108 uses theproperties of the gums and consequently reduces the injection pressure.The injection pressure can be adjusted, for example, by controlling theelectrical input signal applied to the actuator 125 and/or the currentpulse rise time and/or duration. When used on teeth, the controller mayincrease the injection pressure. The injection pressure may be adjusteddepending on location of the skin on the body, for example, the faceversus the arm of the patient. Moreover, the injection pressure may bevaried over time. For instance, in some implementations, a largeinjection pressure is initially used to loosen cavity, and then a lowerinjection pressure is used to loosen food.

For example, the controller 108 may be coupled with an acoustic sensor1161, such as a piezo-electric sensor or transducer, to measure thedeformation of the biological body in response to a mechanicalperturbation. The piezo-electric transducer may be located at the tip ofthe device, for example, at or near nozzle 114. The transducer may be influid communication with the fluid ejected through nozzle 114 and mayalso be in fluid communication with reservoir 113. In one embodiment,the piezo-electric transducer can be located at the distal end ofplunger 126 (see FIG. 2A). The piezo-electric transducer may emitacoustic signals and sense acoustic signal reflected from the biologicalbody. The acoustic signal may include a high-frequency and/or stochasticsignal.

In more detail, the power source 106 can be external or internal to thedevice 100 or be rechargeable. The power source 106 can include areplaceable battery. Alternatively, the power source 106 includes arechargeable device, such as a rechargeable battery (e.g., gelbatteries; lead-acid batteries; Nickel-cadmium batteries; Nickel metalhydride batteries; Lithium ion batteries; and Lithium polymerbatteries). In some embodiments, the power source 106 includes a storagecapacitor. For example, a bank of capacitors can be charged throughanother power source, such as an external electrical power source.

In more detail, the electromagnetic actuator 125 includes a conductingcoil assembly 104 disposed relative to a magnetic field, such that anelectrical current induced within the coil results in the generation ofa corresponding mechanical force. The configuration is similar, at leastin principle, to that found in a voice coil assembly of a loud speaker.Namely, the relationship between the magnetic field, the electricalcurrent and the resulting force is well defined and generally referredto as the Lorentz force law.

Preferably, the coil 104 is positioned relative to a magnetic field,such that the magnetic field is directed substantially perpendicular tothe direction of one or more turns of the coil 104. Thus, a currentinduced within the coil 104 in the presence of the magnetic fieldresults in the generation of a proportional force directed perpendicularto both the magnetic field and the coil (a relationship referred to asthe “right hand rule”).

An exemplary embodiment of a dynamically-controllable needle-freeinjection device 200 is shown in FIG. 2A. The device 200 includes acompact electromagnetic actuator 202 having a distal force plate 204adapted to abut a proximal end of a plunger 206 of a syringe or ampoule208. The ampoule 208 may, for example, be a commercially availablepolycarbonate ampoule, such as the INJEX™ ampoule. The device 200 alsoincludes a mounting member 212 to which a proximal end of the syringe208 is coupled. A power source (not shown) may also be disposed proximalto the actuator 202, the different components being secured with respectto each other within a housing or shell 216. In some embodiments, acoupler 225 is provided to removably fasten the plunger 206 to theactuator 202. This ensures that the plunger is moved in either directionresponsive to movement of the actuator 202.

FIG. 2B are graphs depicting force-versus-time profiles of components ofexemplary force applied to . . . reservoir 213 in the transfer of asubstance and in tissue identification, the force being generated by thecontrollable electromagnetic actuator of FIG. 2A. As shown, the actuatormay apply a square-wave force component for fluid delivery that ismodulated with a low frequency sinusoidal signal for tissue perturbationand identification. Alternative or in addition, the actuator may alsoapply a stochastic signal for tissue perturbations.

As shown in FIG. 2A, device 200 can include a piezo-electric actuator ortransducer 216H located at the distal end of plunger 206. The transduceris in fluid communication with the fluid ejected through nozzle 214 andin fluid communication with reservoir 213 of ampoule 208. Thepiezo-electric transducer may emit acoustic signals 230 and senseacoustic signals reflected from the biological body, e.g., the tooth orgum. The acoustic signal may include a high-frequency and/or stochasticsignal. The piezo-electric transducer may continuously send an acousticsignal through the fluid and sense the reflection of the signal off atarget surface of the biological body. Information of the emitted andreflected signal can then be used to continuously determine the distanceof the target surface from the transducer, and may be used to measurethe displacement or deformation of the biological body.

Device 200 may include a strain gauge 216F and a position sensor orlinear encoder 216B to sense fluid pressure, including back pressurefrom the ejection of the fluid against tissue, such as tooth, gum, orany other tissue or surface. Sensing pressure using the strain gaugeand/or the position sensor can be used to measure the reaction of tissueto the sinusoidal signal modulating the fluid jet and may be used tosense a surface condition of the tissue.

FIG. 3 is a partial cut-away perspective diagram of the device of FIG.2A illustrating scanning of a fluid jet. The needle-free device 200 mayoperate as a hand-held device moving over the teeth, the gums, thetongue, or other parts of the mouth. The device may include multipledegrees of freedom to be able to scan the teeth from various positionsand orientations. For example, the device 200 may scan the teeth invertical or horizontal (e.g., left and right) directions. FIG. 3illustrates scanning in a horizontal direction as indicated by the arrow300. The needle-free device 200 is highly controllable in terms ofpressure, flow, and velocity and can provide for linear, spiral, orrotary scans, resulting in multi-dimensional coverage of the mouth. Thedevice 200 can eject a fluid against the teeth and the gum in a scanningmotion, sense a surface condition, and control the ejection pressurebased on the sense condition. For example, device 200 can control fluidejection to scan with low pressure and, when on teeth, clean the surfaceof teeth with high pressure. The needle-free device 200 may also be usedin cleaning the surface of the tongue since it can detect the softnessof the tongue and vary its transfer pressure.

In one embodiment, the strain gauge 216F coupled to the ampoule 208(FIG. 2A) is high sensitivity, high bandwidth strain gauge. An exampleof a suitable strain gauge is a general-purpose strain gauge made fromconstantan alloy having a resistance of 120 ohm and gauge factor ofabout 2. With a 2.5 V activation voltage, the strain gauge can achievesensitivity of 5 μV/N and operate at a background noise level of 0.6 μV.Another example of a suitable strain gauge with higher sensitivity is aplatinum-tungsten strain gauge having 350 ohm resistance and a gaugefactor of about 4.5. The strain gauge may be coupled to a controller,such as a NATIONAL INSTRUMENTS™ NI CompactRIO Control and AcquisitionSystem, to power the gauge and collect measurements at, for example, 25k Sample/sec.

FIGS. 4A and 4B are graphs depicting pressure versus time of fluidpressure sensed using a strain gauge and a position sensor,respectively. The fluid pressure sensed comprises the pressure due theactuator ejecting the fluid through a nozzle and the back pressure fromthe fluid jet hitting the target material. Target materials include softmaterials, including air (i.e., ejecting a fluid jet into air), siliconerubber (durometer 30 Shore A), 10% acrylamide gel, and water, as well ashard materials, including steel, glass ceramic, PVC-coatedpolycarbonate, and wood. Some of the target materials, such as thesilicone rubber, are tissue analogs.

FIG. 4A shows the pressure sensed using a strain gauge 216F coupled tothe ampoule 208. The strain gauge measures hoop stress of the ampouleduring fluid ejection. FIG. 4B shows the pressure sensed using a linearencoder 216B that measures the position of the voice coil of theactuator 202, the position being related to the force applied by theactuator to the ampoule during fluid ejection. Both methods of sensingpressure produce pressure profiles that can be used to distinguishbetween hard and soft materials. Both methods may also be used tofurther distinguish among the tested materials in the hard and softgroup of materials. The sensed difference in pressure profilesdue todifferences in material hardness is a material property, or surfacecondition, that can be used to control the ejection of fluid.

FIG. 4C is a graph of peak pressure for ejection of fluid againstmaterials of different surface properties. The value for the hardsurface represents the average of the values obtained for all hardsurfaces measured, including those described with reference to FIG. 4A.The sensed difference in peak pressure with different material hardnessis a material property or surface condition that can be used to controlthe ejection of fluid.

FIG. 4D is a graph of pressure versus angle of injection against a hardsurface, such as a glass ceramic or steel. The graph shows that peakpressure varies with the angle of injection, with the highest pressuremeasured at an angle of about 90 degrees and little variation inpressure for angles between about 80 and 0 degrees. The senseddifference in peak pressure with different ejection angles may be usedto control the ejection of fluid.

Embodiments of the invention may employ a linear Lorentz-force actuatorto propel liquid and/or medicant under pressure at specific sites alongthe tissue-tooth interface in order to expose, identify, and removeplaque from the tooth and gingival crevice with application to bothprofessional and every day oral care. Medicant may be any of a number ofantiseptics, anti-plaque agents, or biomarkers that can improve oralhygiene or aid in the diagnosis of local or systemic disorders.

In certain embodiments, a Lorentz-force actuator is used to propelliquid under pressure to the tissue/tooth interface. The device may be amulti-actuated device that will move along the gum line with thecapability of differentiating between the soft and hard surfacescomprising the target area. The device may house one or moreLorentz-force actuators within a hand grip or housing. The device can bea single or multi actuated device with one or more of the followingproperties:

-   -   Be contiguous with a tip in fluid communication with the target        (e.g., tissue/tooth interface) and a small fluid reservoir.    -   Be in communication with a probe that can be used to        mechanically perturb the tissue/tooth interface and provide        identification of tooth versus tissue within a 2-3 s time        period. In one embodiment, the probe could be attached to a        custom designed linear Lorentz-force actuator and used to apply        a force (<5 N) to the tooth or gum surface (i.e. perturbing the        surface). The tissue responsive to the perturbation can be        displacement analyzed using stochastic system identification as        described in Y. Chen and I. W. Hunter, In vivo characterization        of skin using a Wiener non linear stochastic identification        method. Proceedings of 31^(st) Annual IEEE Engineering in        Medicine and Biology Conference, (2009) 6010-6013, and in U.S.        patent application Ser. No. 12/872,630, filed on Aug. 31, 2010,        entitled “Nonlinear System Identification Techniques and Device        For Discovering Dynamic And Static Tissue Properties”,        incorporated by reference in their entirety. More specifically,        the system (i.e. the actuator, probe tip, and target) is excited        using a Gaussian white noise voltage input which drives the        actuator through a linear power amplifier. The actuator in turn        imposes a force on the probe tip and by extension the target        surface. Analysis of the output (i.e. tissue displacement)        permits one to discriminate the hard tooth surface (high local        stiffness) from the soft tissue or plaque (lower local        stiffness). While mechanically attached to the front of the        coil, the probe could maintain some degree of freedom for        repositioning within/between the teeth. In another embodiment        electrical impedance could be used to differentiate between        tooth and gum.    -   Use one or more strain gauges, attached to the outer face of the        ampoule but well within the volume window, to determine the        deformation of the delivery housing (e.g. ampoule) with a        constant input force (pressure) and variable surface; harder        surfaces (e.g. tooth) exhibiting higher peak pressures than        softer surfaces (e.g. gum).    -   Use light waves to differentiate between tooth and gum since the        regular structure of tooth ensures good propagation through the        enamel and tubules in the dentin. As such, changes in structure        manifest as changes in scattering of light as it passes through        the tooth and in changes in absorption and fluorescence on the        surface of the tooth. These latter changes which are normally        used to differentiate between healthy and caries ridden teeth        can also be used to differentiate between tooth and gum.        Techniques based on these interactions include, but are not        limited to, multiphoton imaging, infrared thermography, infrared        fluorescence, and optical coherence tomography (OCT). Of these        techniques, OCT is most easily adapted for inclusion into the        jet injection device.    -   Use an acoustic wave imposed on the fluid jet together with the        actuation of the linear Lorentz-force actuator to determine the        phase difference or time of flight and force respectively.

The pressure at which fluid is ejected from the tip is servo-controlledwith delivery of fluid into the fluid reservoir and ejection through anarrow orifice (i.e. <500 um) under pressure to deliver a high jetstream of fluid to the tooth-tissue interface. The pressure will bevaried dependent on the interface. Prior to delivery the degree ofpressure required will be determined by evaluating the plaque on toothsurfaces and gingiva using the jet injector.

In one embodiment, the jet injector is used to deliver disclosant dyes[D. A. Baab, A. H. Broadwell, and B. L. Williams, A comparison ofantimicrobial activity of four disclosant dyes, J Dental Res 62 (1983)837-841] to identify dental plaque. It is known that there are severaldye indicators for dental plaque which include, but are not limited to,erythrosin (FCD Red #3) (U.S. Pat. No. 3,309,274), sodium fluorescein(FDC Yellow #8) [in H. Wolf, Color atlas of dental hygiene:periodontology (2006) 225-227], and betanin (U.S. Pat. No. 4,431,628).

In some embodiments, other methods may be used individually or incombination for plaque identification, including:

-   -   Various optical spectroscopic techniques (e.g. scattering,        absorption, and fluorescence in the visible or infrared) which        can be accomplished by shining a laser beam down the delivery        channel when using a semi transparent jet of liquid. This can        also include OCT technologies.    -   Raman spectroscopy or faster techniques such as coherent Raman,        Coherent Anti-Stocks Raman Spectroscopy (CARS) (e.g. broadband,        time resolved, frequency-modulated), and Optical        Heterodyned-Detected Raman-Induced Kerr Effect (OHD-RIKE). These        methods may also provide information relating to the microbial        composition based on known or identified Raman spectra peaks.    -   Various sound wave technologies (e.g. ultrasound, elastography),        where one can use the phase difference, time of flight, and        reflection response peak intensities to distinguish plaque from        tooth.    -   Nuclear Magnetic Resonance (NMR).

The above techniques singly or in combination may be coupled or combinedwith stochastic system identification techniques to determinedifferences in material properties. The state of the tooth/tissueinterface, as detected by one or more of the above techniques, can beused to determine, in real time, the waveform required to mechanicallyremove plaque from the specific tooth tissue interface.

Plaque removal can be accomplished by delivery of a high pressure jet offluid, such as water, medicant, or both. Medicant can include, but isnot restricted to, chelating agents, fluoride (known to inhibit theability of oral bacteria to create acid) or fluorescent dyes or probesused to detect bacterial specific changes (e.g. pH etc.) and/orbiochemical specific biomarkers. Delivery of said medicants may alsoemploy controlled release packaging such as gel like fluid, particles,or solids. Delivery of such medicants has been demonstrated by theability of the ejector device to deliver colored beads to thesubgingival space as described with reference to FIGS. 5A-5D. Severalarticles reviewing potential targets and the use of saliochemistry as adiagnostic tool have been published [J. K. M. Aps and L. C. Martens,Review: The physiology of saliva and transfer of drugs into saliva.Forensic Sci International 150 (2005) 119-131; F. M. L. Amado, R. M. P.Vitorino, P. M. D. N. Dominigues, M. J. C. Lobo, and J. A. R. Duarte,Analysis of the human saliva proteome, Exp Rev Proteomics 2 (2005)521-539; B. J. Baum, A. Voutetakis, and J. Wang, Salivary glands: noveltarget sites for gene therapeutics, TRENDS Mol Med 10 (2004) 585-590; E.Kaufman and I. B. Lamster, The diagnostic applications of saliva-areview, Crit Rev Oral Biol Med 13 (2002) 197-212; A. Aguirre, L. A.Testa-Weintraub, J. A. Banderas, G. G. Haraszthy, M. S. Reddy, and M. J.Levine, Critical reviews in oral biology & medicine, Sialochemistry: Adiagnostic tool 4 (1993) 343-350].

FIGS. 5A-5D show the delivery of water and 6 μm beads to the subgingivalspace using jet injector 500. Typodont and/or dentiform tooth and gummodels can be used to evaluate the delivery of black polystyrene beadsto the sulcus, which is the natural space between the tooth and the gumsurface. FIG. 5A shows typodont 501, which is a model of the oralcavity, including teeth 502, gingival 504, and the palate (not shown).The typodont 501 can include polymers of different stiffness for thegingiva, or gums, 504. FIG. 5A shows the delivery of water 512 to thetooth/gum interface of typodont model 501 using the jet injector 500.Only part of the jet injector, the distal end of the ampoule orreservoir, is visible. FIG. 5B shows the delivery beads 514 and water tothe tooth/gum interface of the typodont model 501 using the jetinjector. The delivery waveform was tailored to eject a solution ofbeads at 100 m/s for 10 seconds in order to separate the tooth and gumfollowed by delivery of the remaining solution at 10 m/s in order todeposit bead into the sulcus. FIG. 5C shows the typodont model 501 afterdelivery of beads to the gum line 506 using the jet injector. FIG. 5Dshows the typodont model of FIG. 5C with the gum 504 partly pulled awayby probe 510 to expose the beads delivered to the sulcus 508. Deliveryof beads to the sulcus demonstrates the use of the jet injector, such asdevice 200 of FIG. 2A, for delivery of medicant to this area.

In some embodiments, identification and/or removal of plaque may becoupled with oral diagnostics, including, for example, detection orchange in concentration of an analyte (e.g. antigen, antibody, nucleicacid etc.) in a fluid. The jet injector may be used to remove a smallvolume of saliva either pre- or post-brushing/cleaning to evaluate oralhealth and/or systemic health.

In one embodiment, the jet injector can be used to remove a small amountof fluid that would be mixed with a conjugated antibody (fluorescent,enzymatic etc.), and loaded into a microtiter plate, the wells of whichcontain antibody to the antigen(s) of interest. Binding would bedetected by addition of an appropriate substrate.

In another embodiment, saliva may be collected into a modified,disposable tip lined with a solid support or matrix containing anantibody array. Detection would involve inclusion of a second, specificlabeled antibody or enzyme-antibody conjugate with subsequent substrate.Unbound analyte and binding reagent would be removed by delivery andremoval of a wash solution after each binding reaction using thebi-directionality of the linear Lorentz-force actuator.

FIG. 6 shows an exemplary device 600 for detecting an analyte from asample collected in a disposable tube. The device uses a disposable,spherical tube (e.g. straw) 602 for the collection of saliva. Aftercollection, the tube is placed within a non-disposable detector oranalyzer 604. In one embodiment, fluid, such as saliva, may be depositedor drawn directly into a disposable, spherical tube 602, using the jetinjector device, reacted with specific, labeled or conjugated bindingreagent (e.g. fluorophore or enzymatic respectively) dried onto theinner surface of the straw at a specific location, and then absorbedonto a solid support or matrix, for example a polymer, containing one ormore antibodies of interest bound at a specific site. At this point, thestraw 602, if still attached to the jet injector device, can be removedand slid into the non-disposable detector 604. Unbound analyte andbinding reagent may be removed by passage of a wash solution through thestraw followed by substrate if using an enzyme conjugate. The device 600may include user controls, such as power button 606, to start andcontrol the analysis and measurement. A display 608 may also be includedto display the results of the measurement to the user. Detector oranalyzer 604 may, for example, include detector 1000 described withreference to FIG. 10.

In some embodiments, a detector or analyzer, such as detector 600, maybe integrated into the jet injector. As shown in FIG. 1, optionaldetector or analyzer 122 may be coupled to or included in theneedle-free injector 100 to detect a marker of oral health using theanalyzer 122. The injector 100 may control ejection of a substanceagainst tooth or gum responsive to the detected marker. In oneembodiment, the jet injector uses a Lorentz-force actuator to eject thesubstance, which may be fluid or a fluid containing a medicant. Becausethe Lorentz-force actuator is bi-directional, depending upon thedirection of the coil current, the same device used to inject asubstance can also be used to withdraw a sample. This is a beneficialfeature as it enables the device to collect a sample.

Referring to FIG. 7A, an exemplary sampling, needle-free injector 700 isillustrated. The sampling jet injection device 700 includes abi-directional electromagnetic actuator 702 abutting at one end a firstpiston 714A. A sampling nozzle 711A is coupled at the other end of asyringe or ampoule 710. The actuator 702 is controlled by controller704. Controller may include a power source (not shown), such as abattery or suitably charged storage capacitor, to power the actuator702. The first piston 714A is slidably disposed within a samplingsyringe 710, such that an electrical input signal applied to theactuator 702 withdraws the first piston 714A away from the samplingnozzle 711A. A sample can be collected from an oral cavity or a surfacewhen the sampling nozzle 711A is placed in the oral cavity or near thesurface during actuation. Collecting a sample may include first ejectinga substance into the oral cavity or against a surface and thenwithdrawing a sample that includes at portion of the ejected substanceand a biological sample, e.g., a biological fluid.

Referring now to FIG. 7B, once a sample has been collected, a movablesyringe mount 708 can be re-positioned such that the sampling syringe710 is aligned with an analyzer or detector 706. By the same motion, asecond syringe 712 having a second piston 714B and including asubstance, such as a fluid, cleansing agent, or medicant, is alignedwith the actuator 702. The mount 708 may be a rotary mount rotatingabout a longitudinal axis or a linear mount as shown. The analyzer ordetector 706 provides a control signal to the controller 704 responsiveto the analyzed sample. The control signal, via controller 704, causesthe actuator 702 to push the second piston 714B forward therebyexpelling an amount of the substance responsive to the analyzed sample.Thus, the same device 700 can be used to both collect a sample and toeject a substance. In an embodiment, the jet injector device may includetwo jet injectors and/or actuators, one to sample and the other to ejecta substance responsive to the analyzed sample.

In yet another embodiment, a polymer strip containing plaque-specificbiomarkers, for example Streptococcus species, is attached to adisposable head of a tooth brush or tooth brush-like device. FIG. 8shows an example of a disposable, polymer strip 802 containing aplaque-specific biomarker attached to the head of a toothbrush ortoothbrush-like device 800. The strip 802 can be attached to or includedin a disposable top section 810 or device 800. The strip 802 may becoupled to or in fluid communication with a sensor section 804 of device800 via top section 810. When inserted into the mouth, the polymer stripwill absorb saliva and bind analyte(s) of interest. The strip can thenbe peeled away and processed as above or the strip can be analyzed bysensor 804 on the device itself. For example, binding of an analyte ofinterest, such as a plaque-specific biomarker, can be determined by achange in impedance. Binding of an analyte can also be determined by achange in absorbance or fluorescence, as for example by enzyme linkedimmunoabsorbant assay (ELISA). The device can include a power andmeasurement button 806 to initiate the analysis. A display 808 may beincluded to display results of the analysis to a user.

The above embodiments may be configured or modified to detect changes inantibody concentration, for example IgA, a common component of themucosal immune system. In this case, the analyte would bind to aspecific antigen with detection by a labeled secondary antibody, as forexample described below with reference to FIGS. 9A-9B and FIG. 10.

FIGS. 9A-9B illustrate the use of disposable, polymeric strips toevaluate oral health status. FIG. 9A is schematic diagram showingbinding of an analyte 904 (in this case antibody) to a solid support 900(in this case a polypyrrole film strip) to which antigen 902, specificto the analyte of interest, can be adsorbed, entrapped, or covalentlyattached. Prior to the addition of analyte, unbound antigen is removedby washing and free sites on the polymer strip blocked to preventnon-specific binding of successive reagents. Addition of analyte 906followed by washing and blocking prior to the addition of labeledsecondary antibody specific to the analyte. The secondary antibody maybe conjugated to a fluorophore or enzyme, for example horseradishperoxidase (HRP) 908 as shown. In this latter case, binding is detectedby the addition of a substrate 910 that, in the presence of HRP, yieldsa colored product that can be detected by reading absorbance.Alternatively, binding of primary antibody could be detected bymeasuring a change in electrical impedance. FIG. 9B is a plot of ELISAresults showing increase in absorbance observed with absorption ofincreasing concentrations of antigen into polypyrrole film strips.

FIG. 10 is a schematic diagram showing a detector for detecting a markeror analyte of oral health status, such as a labeled or conjugatedantibody shown in FIG. 9A. The detector 1000 consists of a light source1002 that excites the sample 1004 with light 1003, and photodiode 1006to measure the light emitted from the sample. Sample 1004 includes themarker or analyte of interest. Detector 1000 further includes a lens1008 to focus the light of the light source 1002 on the sample 1004, anda dichroic mirror 1010 to reflect the light emitted from the samplethrough a second lens 1009 and into the photodiode 1006. Light source1002 may include a light-emitting diode (LED). Sample 1004 may besupported by or deposited on a solid support 1012, which may include apolymer strip, such as strip 900 described with reference to FIG. 9A.

Alternatively or in addition to optical detection, binding of a markeror analyte may also be detected using electrical impedance. Furthermore,saliva samples obtained using the jet injector could be processeddirectly using Coherent Raman spectroscopy.

The devices and techniques described herein provide a means ofquantifying specific bacterium, antibody, etc. relevant to oral healthand disease and thereby a means of determining effective and appropriateintervention strategies.

The teachings of all patents, published applications and referencescited herein are incorporated by reference in their entirety.

While this invention has been particularly shown and described withreferences to example embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

For instance, although the particular embodiments shown and describedherein relate in general to dental cleaning and treatment applications,it will further be understood that the principles of the presentinvention may also be extended to other medical, non- medical, andindustrial cleaning and surface treatment applications, including, forexample, cleaning of household appliances, such as ovens, and treatmentand cleaning of surfaces, such as surfaces in bathrooms and kitchens.The issue in each case is to sense a surface condition, for examplehardness of bathroom tiles as opposed to the softness of grout, andcontrol ejection of a fluid jet against a surface, e.g. the tilesurface, to treat the surface based on the sensed condition. Embodimentsof the present invention the ejection is controlled to clean a part ofthe surface, e.g. a part of an appliance made from ceramics or metal, athigh pressure and to reduce pressure applied to another part of thesurface, e.g. a part of an appliance made from silicone rubber, such asa gasket. Devices and methods described herein may be used to remove anycombination of grime, grease, lime scale, bacterial film and mildew fromthe surface.

1. A method of surface treatment comprising: sensing a surfacecondition; and controlling ejection of a fluid jet against a surface totreat the surface based on the sensed condition.
 2. The method of claim1 wherein the fluid is liquid.
 3. The method of claim 2 wherein thefluid is carried in a self-contained reservoir in a handle of a fluidejection device.
 4. The method of claim 3 wherein the reservoir is lessthan 100 milliliters.
 5. The method of claim 2 wherein the liquid is acleansing solution.
 6. The method of claim 2 wherein the liquid containscleaning particles.
 7. The method of claim 1 wherein the jet is of adiameter of less than 500 microns.
 8. The method of claim 1 wherein thejet is of a diameter of less than 200 microns.
 9. The method of claim 1wherein the ejection is controlled at a bandwidth of at least 10 hertz.10. The method of claim 1 wherein the ejection is controlled at abandwidth of at least 50 hertz.
 11. The method of claim 1 wherein theejection is controlled at a bandwidth of at least 100 hertz.
 12. Themethod of claim 1 wherein the ejection is controlled at a bandwidth ofat least 1 kilohertz.
 13. The method of claim 1 wherein the fluid isejected at a peak relative pressure of at least 1 kilopascal.
 14. Themethod of claim 1 wherein the fluid is ejected at a peak relativepressure of at least 100 kilopascals.
 15. The method of claim 1 whereinthe fluid is ejected at velocity of at least 1 meter per second.
 16. Themethod of claim 1 wherein the fluid is ejected at velocity of at least10 meters per second.
 17. The method of claim 1 wherein the ejection iscontrolled to clean a part of the surface at high pressure and to reducepressure applied to another part of the surface.
 18. The method of claim17 to clean the surface.
 19. The method of claim 17 wherein less than100 milliliters of liquid is ejected per cleaning session.
 20. Themethod of claim 1 further comprising automatically scanning the fluidjet relative to a handle of an injection device.
 21. The method of claim1 wherein the fluid is ejected by means of a fluid ejector comprising astationary magnet assembly providing a magnetic field and a coilassembly, slidably disposed with respect to the magnet assembly, thecoil assembly driving ejection of the fluid jet.
 22. The method of claim1 wherein sensing the surface condition comprises measuring a responseof the surface to a mechanical perturbation.
 23. The method of claim 22wherein the mechanical perturbation comprises applied force and themeasured response comprises deformation of the surface.
 24. The methodof claim 22 further comprising mechanically disturbing the surface withthe fluid jet.
 25. The method of claim 22 wherein measuring a responsecomprises measuring pressure of the fluid.
 26. The method of claim 25wherein measuring pressure comprises sensing strain of a fluidreservoir.
 27. The method of claim 25 wherein measuring pressurecomprises sensing position of an actuator driving the ejection of thefluid.
 28. The method of claim 1 wherein sensing the surface conditioncomprises generating an acoustic signal and sensing the acoustic signalreflected from the surface.
 29. The method of claim 28 wherein theacoustic signal travels through the fluid jet.
 30. The method of claim28 wherein the acoustic signal is sensed using a piezo-electrictransducer.
 31. The method of claim 30 wherein the acoustic signal isgenerated and sensed using a piezo-electric transducer.
 32. The methodof claim 28 wherein the acoustic signal comprises a stochastic signal.33. The method of claim 28 wherein sensing the surface condition furthercomprises measuring surface deformation with applied force using thesensed acoustic signal.
 34. The method of claim 33 wherein the force isapplied using the fluid jet.
 35. The method of claim 1 furthercomprising sensing motion of a fluid ejector and controlling theejection of the fluid jet based on the sensed motion.
 36. The method ofsurface treatment comprising: ejecting a fluid jet against a surface,the jet having a diameter of less than 500 microns, a peak relativepressure of at least 1 kilopascal and velocity of at least 1 meter persecond.
 37. The method of claim 36 wherein the fluid is liquid.
 38. Themethod of claim 37 wherein the fluid is carried in a self-containedreservoir in a handle of a fluid ejection device.
 39. The method ofclaim 38 wherein the reservoir is less than 100 milliliters.
 40. Themethod of claim 36 wherein the jet is of a diameter of less than 200microns.
 41. The method of claim 36 wherein the fluid is ejected at apeak relative pressure of at least 100 kilopascals.
 42. The method ofclaim 36 wherein the fluid is ejected at velocity of at least 10 metersper second.
 43. The method of claim 36 wherein the fluid jet iscontrolled at a bandwidth of at least 10 hertz.
 44. The method of claim36 wherein the fluid jet is controlled at a bandwidth of at least 50hertz.
 45. The method of claim 36 wherein the fluid jet is controlled ata bandwidth of at least 100 hertz.
 46. The method of claim 36 whereinthe fluid jet is controlled at a bandwidth of at least 1 kilohertz. 47.The method of claim 36 for removing any combination of grime, grease,lime scale, bacterial film and mildew from the surface.
 48. The methodof claim 36 further comprising automatically scanning the fluid jetrelative to a handle of an injection device.
 49. The method of claim 36wherein the fluid is ejected by means of a fluid ejector comprising astationary magnet assembly providing a magnetic field and a coilassembly, slidably disposed with respect to the magnet assembly, thecoil assembly driving ejection of the fluid jet.
 50. A hand-held surfacetreatment device comprising: a housing configured to be held on hand; afluid ejector positioned at an end of the housing that ejects fluidagainst a surface in a scanning movement relative to the housing. 51.The device of claim 50 wherein the fluid is liquid.
 52. The device ofclaim 51 further comprising a self-contained reservoir of the liquid inthe housing.
 53. The device of claim 52 wherein the reservoir is lessthan 100 milliliters.
 54. The device of claim 50 wherein the scan isgreater than 1 millimeter.
 55. The device of claim 50 further comprisinga servo controller controlling pressure of ejected fluid in response toa sensed surface condition.
 56. The device of claim 55 wherein thesensed surface condition comprises a mechanical property of the surface.57. The device of claim 55 further comprising a pressure sensor thatsenses pressure of the fluid in the ejector.
 58. The device of claim 57wherein the pressure sensor comprises a strain gauge that senses strainof a reservoir of the ejector.
 59. The device of claim 57 wherein thepressure sensor comprises a position sensor that senses position of anactuator driving the ejection of the fluid.
 60. The device of claim 50further comprising a distance sensor that senses distance of the ejectorfrom the surface.
 61. The device of claim 60 wherein the distance sensorcomprises a piezo-electric transducer and the distance is sensed usingan acoustic signal.
 62. The device of claim 50 further comprising aservo controller controlling pressure of ejected fluid in response to asensed motion of the ejector.
 63. A method of surface treatmentcomprising: ejecting a fluid jet against a surface; and scanning thefluid jet relative to a handle of an injection device.
 64. The method ofclaim 63 wherein the fluid is liquid.
 65. The method of claim 63 furthercomprising controlling pressure of ejected fluid based on a sensedsurface condition.
 66. The method of claim 63 further comprisingcontrolling pressure of ejected fluid based on a sensed motion of theinjection device.
 67. The method of claim 63 for removing anycombination of grime, grease, lime scale, bacterial film and mildew fromthe surface.
 68. A surface treatment device comprising a fluid ejectorthat ejects a fluid jet against a surface, the jet having a diameter ofless than 500 microns, a peak relative pressure of at least 1 kilopascaland velocity of at least 1 meter per second.
 69. The device of claim 68wherein the fluid is liquid.
 70. The device of claim 69 furthercomprising a housing configured to be held on hand, the fluid ejectorbeing positioned at an end of the housing.
 71. The device of claim 70further comprising a self-contained reservoir of the liquid in thehousing.
 72. The device of claim 71 wherein the reservoir is less than100 milliliters.
 73. The device of claim 68 further comprising a servocontroller controlling pressure of ejected fluid in response to a sensedsurface condition.
 74. The device of claim 73 wherein the sensed surfacecondition comprises a mechanical property of the surface.
 75. The deviceof claim 73 further comprising a pressure sensor that senses pressure ofthe fluid in the ejector, and wherein the surface condition is sensedbased on the sensed pressure.
 76. The device of claim 73 furthercomprising an acoustic transducer that senses an acoustic signalreflected off the surface, and wherein the surface condition is sensedbased on the reflected acoustic signal.
 77. A surface treatment devicecomprising: a fluid ejector that ejects fluid against a surface to treatthe surface; and a servo controller controlling pressure of ejectedfluid in response to a sensed surface condition.
 78. The device of claim77 wherein the fluid is liquid.
 79. The device of claim 77 wherein thesensed surface condition comprises a mechanical property of the surface.80. The device of claim 77 further comprising a pressure sensor thatsenses pressure of the fluid in the ejector, and wherein the surfacecondition is sensed based on the sensed pressure.
 81. The device ofclaim 77 further comprising an acoustic transducer that senses anacoustic signal reflected off the surface, and wherein the surfacecondition is sensed based on the reflected acoustic signal.